There’s an old Cold War joke — pre-pantyhose — that to defeat communism we should empty our B-52 bombers of nuclear weapons and instead drop nylons over the Soviet Union. Flood the Russians with the soft consumer culture of capitalism, seduce them with Western contact and commerce, love-bomb them into freedom.

We did win the Cold War, but differently. We contained, constrained, squeezed and eventually exhausted the Soviets into giving up. The dissidents inside subsequently told us how much they were sustained by our support for them and our implacable pressure on their oppressors.

The logic behind President Obama’s Cuba normalization, assuming there is one, is the nylon strategy. We tried 50 years of containment and that didn’t bring democracy. So let’s try inundating them with American goods, visitors, culture, contact, commerce.

It’s not a crazy argument. But it does have its weaknesses. Normalization has not advanced democracy in China or Vietnam. Indeed, it hasn’t done so in Cuba. Except for the United States, Cuba has had normal relations with the rest of the world for decades. Tourists, trade, investment from Canada, France, Britain, Spain, everywhere. An avalanche of nylons — and not an inch of movement in Cuba toward freedom.

In fact, one could argue that this influx of Western money has helped preserve the dictatorship, as just about all the financial transactions go through the government, which takes for itself before any trickle-down crumbs are allowed to reach the ­regime-indentured masses.

My view is that police-state control of every aspect of Cuban life is so thoroughly perfected that outside influences, whether confrontational or cooperative, only minimally affect the country’s domestic trajectory.

So why not just lift the embargo? After all, the unassailable strategic rationale for isolating Cuba — in the Soviets’ mortal global struggle with us, Cuba enlisted as a highly committed enemy beachhead 90 miles from American shores — evaporated with the collapse of the Soviet empire. A small island with no significant independent military capacities, Cuba became geopolitically irrelevant.

That’s been partially reversed in the past few years as Vladimir Putin has repositioned Russia as America’s leading geopolitical adversary and the Castros signed up for that coalition too. Cuba has reportedly agreed to reopen the Soviet-era Lourdes espionage facility, a massive listening post for intercepting communications. Havana and Moscow have also discussed the use of Cuban airfields for Russia’s nuclear-capable long-range bombers.

This in addition to Cuba’s usual hemispheric mischief, such as training and equipping the security and repression apparatus in Venezuela.

No mortal threat, I grant you. And not enough to justify forever cutting off Cuba. But it does raise the question: With the U.S. embargo already in place and the Castros hungry to have it lifted, why give them trade, investment, hard currency, prestige and worldwide legitimacy — for nothing in return?

Obama brought back nothing on democratization, a staggering betrayal of Cuba’s human rights crusaders. No free speech. No free assembly. No independent political parties. No hint of free elections. Not even the kind of 1975 Helsinki Final Act that we got from the Soviets as part of detente, granting structure and review to human rights promises. These provided us with significant leverage in supporting the dissident movements in Eastern Europe that eventually brought down communist rule.

If Obama insisted on giving away the store, why not at least do it item by item? We relax part of the embargo in return for, say, Internet access. And tie further normalization to serial relaxations of police-state repression.

Oh, what hypocrisy, say the Obama acolytes. Did we not normalize relations with China and get no human rights quid pro quo?

True. But that was never a prospect. The entire purpose was geopolitical and the payoff was monumental: We walked away with the most significant anti-Soviet strategic realignment of the entire Cold War, formally breaking up the communist bloc and gaining China’s neutrality, and occasional support, in our half-century struggle to dismantle the Soviet empire.

From Cuba, Obama didn’t even get a token gesture. Not even a fig leaf such as, say, withdrawal of secret police support in Venezuela. Or extradition of American criminals now fugitive in Cuba, including a notorious cop killer. Did we even ask?

Obama seems to believe that the one-way deal was win-win. A famous victory — the Cuba issue is now behind us. A breakthrough.

Indeed it is. You know how to achieve a breakthrough in tough negotiations? Give everything away. Try it. You’ll have a deal by noon. Every time.